What are the common CRISPR selection markers?

Common CRISPR selection markers include: fluorescent proteins (e.g. GFP), antibiotic resistant genes (e.g. ampicillin), and drugs (e.g. imatinib). Researchers have transformed catalytically inactive dCas9 by attaching GFP to it. This modification allows dCas9 to function as a unique DNA label, which can be then observed using fluorescence microscopy in viable cells. CRISPR experiments can be designed to disrupt or knock out specific genes involved in drug resistance. Cells with successful gene knockout can survive drug treatment, while cells without the knockout will not. Antibiotic resistance genes are often used in plasmids containing CRISPR-Cas components. Cells transfected with the CRISPR construct can survive antibiotic treatment, while the other cells will not be able to.